The prior art is replete with portable devices of the type described above that merge pressure sensitive adhesive coated tape with sheet masking material supplied from rolls of the tape and masking material carried on the devices. U.S. Pat. Nos. 3,787,271; 4,379,019; 4,425,182; and 4,508,587 provide illustrative examples.
The portable device of this type described in U.S Pat. No. 4,379,019 comprises a frame including a hub support portion and a handle adapted for manual engagement to manipulate the device, and first and second hubs mounted on said frame for rotation about spaced generally parallel axes. The first hub includes means for receiving the roll of tape and positioning a first edge of the length of tape at a first predetermined position axially with respect to the first and second hubs with the second edge of the length of tape projecting past the frame, and the second hub is adapted to receive the roll of masking material and position a first edge of the length of masking material at a second predetermined position axially with respect to said first and second hubs with the width of the length of tape extending from the first position past the second position and the width of the length of masking material extending from the second position past the first position so that a portion of the length of tape along the first edge of the length of tape and a portion of the length of masking material along the first edge of the length of masking material are both positioned between those first and second positions. The device also includes path defining means defining a path for the length of tape from the roll of tape along which path the second edge of the tape is not guided, and a path for the length of masking material from the roll of masking material. The paths defined by the path defining means include a tape path portion for the tape from the roll of tape to the periphery of the roll of masking material and a common path portion beginning at the periphery of the roll of masking material where the portion of tape along the first edge of the length of tape is adhered to the portion of the masking material along the first edge of the length of masking material to form a composite masking sheet having opposite edges defined by the second edges of the length of tape and the length of masking material and an exposed portion of the coating of pressure sensitive adhesive along the second edge on the length of tape along one major surface of the composite masking sheet so that the exposed portion of the coating of adhesive can be adhered along a surface to be masked to hold the composite masking sheet in a desired position.
The tape being adhered along the edge portion of the masking material by such a device has a tendency to move transversely away from the masking material with respect to the first edge of the masking material so that less and less of the tape is adhered to the masking material. Such lateral tracking of the tape has some tendency to occur with the types and widths of tapes (e.g., 3/4 inch wide masking tape) and masking materials (e.g., craft paper) most often used on such devices, has even a greater tendency to occur when wider widths of tape or tapes with more aggressive adhesive (e.g., duct tapes) are applied to the masking material (e.g., tape having a width of two inches can track laterally sufficiently to separate from the first edge of the masking material), and is particularly pronounced when tape is applied to the soft edge portion of a roll of folded plastic masking material.